Major Product Improvements on the Mellow Drive


13 February 2018

Some of you might have noticed that we’ve been a bit quieter over the last 2 months. This was for a good reason: We've used the slow winter months for fine-tuning and improving the Mellow Drive. 



Although, with our high-quality standards we are always striving for 100%, we have to admit that like any new product entering the market our first production series 2017 had a few teething problems.


Reported Issues

There have been 4 main issues that Mellow owners reported to us:
1. Batteries were rattling inside of the Drive
2. Batteries dropped out of the Drive
3. Battery wouldn’t charge anymore
4. Drive didn’t work anymore after water entered the system


These issues didn’t affect all Mellow owners. Many of our customers never reported any issues and still are perfectly happy with their Drive. Depending on the production series and fit of components some Mellow systems were more affected than others.



The good news is: We found the reasons and solutions for all the issues and fed them into our production processes. Thereupon we did some extreme real life testing to prove that the Mellow Drive 2018 series, which we will start to ship in March, finally completely meets our product promises.



All customers that have been affected by any issue will benefit from the improvements as well as they are covered by our 2-year-warranty. Plus, in the upcoming weeks all Mellow owners will receive a care-package with a set of pads to implement into their drives to solve the problems 1 and 2 (rattling & drop-out). If you experience problem 3 or 4 please get in contact with our customer service via We will analyze the problem and  if necessary provide a replacement as soon as possible. Again: Only a part of the Mellow Drive systems produced in 2017 are affected at all.


Detailed Product Improvements


Electronics Compartment


Problem: Water Resistance

Improvement: Reinforcement of electronics compartment silicone seal


The original seal, which is dispensed onto the electronic compartment cover, could bend away in some cases allowing water into the drive. In order to meet this issue the seal was reinforced to avoid the bending. This measure was confirmed as effective and is in all 2018 Drives.



Electronics Compartment


Problem: Water Resistance

Improvement: Clamping device installed for mounting of electronic compartment lid


While tightening the screws of the electronic compartment the lid has to be pressed down quite firmly in order to bring the necessary pressure onto the seal. This pressing down used to be done by hand and therefore the water resistance was depending on how well this job was performed. TQ created a clamping device to increase the quality in this step of production. The lid is now pressed down with a defined force by the clamp, which makes this step free of the risks of the "human factor".


Electronics Compartment


Problem: Water Resistance

Improvement: 2x UV resin sealing of electronic compartment screws


The screws of the electronics compartment are now sealed in two layers with a UV curing resin. A UV light system was installed and every screw is separately checked for proper application of the resin.



Electronics Compartment


Problem: Water Resistance

Improvement: Gluing of plastic insert into the drive done by robot with extra surface treatment


As there were adhesion issues between the powder coating of the drive and the plastic insert that carries the main battery connector over 250 gluing tests were conducted. The result now is a super strong bond that is permanently watertight. This was achieved i.e. by a plasma pre treatment of the gluing area as well as the use of an industrial robot applying the perfect amount of glue to each frame. Also here the "human factor" was taken out in order to achieve reproducible quality.





Problem: Water Resistance

Improvement: Pressure test


100% of our drives are now pressure tested at the end of production. This means that at the end of the assembly line the drive is "pumped up" with air via the main battery connector and the airtightness is measured. A Drive that holds the pressure is also 100% waterproof.





Problem: Water Resistance

Improvement: Grease-filling of motor-hanger-gap


To improve the longevity of the internal motor bearing we introduced a grease-filling into the gap between the motor and the hanger. This filling keeps water out and protects the bearing.





Problem: Rattling Wheels

Improvement: Improved fit of the wheel on the motors


By tightening the fit of the wheels on our motors we achieved a massive reduction in riding noise and rattling





Problem: Water Resistance

Improvement: Rubber plugs now have thicker sealing ribs


The height of the sealing ribs on the batteries rubber plugs has been increased. This makes the opening and closing of the plugs a bit more firm but it increases the water resistance tremendously.





Problem: Water Resistance

Improvement: Introduction of a rubber gasket under the LED display


Formerly the LED-display was only glued in - now it is equipped with an additional rubber gasket.





Problem: Broken Snap Lock

Improvement: Introduction of 4 ribs on the backside of the snap lock


In order to increase the strength of the snap lock 4 ribs were introduced on the backside.





Problem: Battery Drop

Improvement: Introduction of a shock absorber behind the battery snap lock


As a consequence to a shock the battery's snap lock could start vibrating, allowing the battery to drop out. We introduced a shock-absorbing pad behind the snap lock of the battery that absorbs the energy of the shock, not allowing the snap lock to vibrate. This way the battery stays in place even on a 1m drop. 

mellow-drive-shock-absorber-snap-lock mellow-drive-drop-test




Problem: Rattling / Battery Drop

Improvement: Introduction of lateral pressure pads


Lateral pressure pads now improve the fit of the battery inside the frame and largely reduce vibration of the battery. This measure also reduces the risk of the battery dropping out.





Problem: Rattling / Battery Drop

Improvement: Improved flatness of the battery housing


By adding ribs beneath the blue over-molding material we now achieved that the batteries are flatter and therefore fit more tightly in the frame. This reduces vibration, rattling and the risk of battery dropouts.





Problem: Rattling / Battery Drop

Improvement: Change of blue battery over-molding material


By changing the blue over-molding material to a slightly harder compound with less shrinkage (on cooling after injection) we further improved the batteries flatness with the consequences stated above.





Problem: Rattling / Battery Drop

Improvement: Tightening the battery pockets


At the rear end of the battery left and right of the snap lock have always been two pockets that are now made much smaller in order to firmly bite onto the dedicated metal ribs in the frame. These pockets were there from the beginning as a backup measure for improving the batteries fit and stability and are now being "activated" as we see the necessity.

By tightening the pockets the battery is fixed in position on two additional points now, which reduces the risk of battery dropouts and rattling.





Problem: Burnt-out Charging Fuse

Improvement: Change of fuse to a stronger one


One of the most common battery problems was the burning out of the charging fuse. In order to eliminate this problem the fuse was replaced by a stronger one for the 2018 models.






Problem: Connection Interruption

Improvement: Doubling of Bluetooth signal strength


In order to meet the very rare chance of a connection loss due to a i.e. carbon fiber deck we doubled the signal strength of our remote control.






Problem: Decalibration

Improvement: Software and hardware improvements


As some of our remotes would decalibrate over time we introduced several changes into the remotes electronic hardware as well as compensation algorithms that automatically recalibrate the remote on the fly.





Problem: Decalibration

Improvement: Additional QC-check


At the end of the assembly line all of our remotes get checked for faulty calibration and are recalibrated if necessary.





Problem: Decalibration

Improvement: Recalibration feature


If necessary the customer can now recalibrate the remote very easily by a new firmware feature we introduced on the 2018 series. Our support team will guide the customer through the easy steps of recalibration.






Problem: Lost Connection

Improvement: Increase of transmission strength


In order to meet our customers complaints of the loss of Bluetooth connection we doubled the transmission strength via a firmware update - so this fix is in all remotes that will be delivered in 2018 and will be available for update to all earlier customers in spring.






Problem: Urethane being too thin

Improvement: 90mm wheels are coming!


We are currently working on a 90mm wheel with a urethane durometer in the range of 74A - 80A. These wheels will become available in spring 2018.



We are truly sorry for the inconveniences for everyone who has experienced any troubles with his or her Mellow Drive so far! Be sure that we will replace any faulty component within our 2-year-warranty.


After testing and shredding the iterated 2018 series really hard we are excited about the new season and invite everyone to test the Mellow Drive!


If you want to know if we will be available in a shop close to you really soon stay tuned via our Mellow News!

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